This research program has had as its goal the control of biological functions, such as growth, by the application of biophysical techniques. In order to accomplish this, knowledge of the biophysical properties that are naturally present in living organisms must be obtained. Our knowledge and understanding in this latter area has progressed sufficiently in the past year to enable us to describe in detail the control system regulating regenerative type growth (regrowth of an arm or leg after amputation). This led us to begin experimentation on the possibility of restoring this type of growth to animals such as mammals, not normally capable of it. The experiments have been successful in producing the regrowth of organized bones, joints and muscles in amputated limbs of white laboratory rats. This is the first time that this result has been produced despite many attempts to do so since the scientific study of regeneration first began in the 16th century. These results have considerable clinical significance for the regrowth of lost or damaged structures in man and possibly for the control of abnormal growth as well. We hope to continue experimentation along these lines at an increased pace in the next few years.